1. Field of the Invention
This invention relates to jib booms used with cranes and telescopic boom assemblies, particularly to a hydraulically powered jib boom (of both swing jib and non-swing jib design) with an optional self-contained work platform attachment having auto-powered leveling and 360-degree rotation that can be used with mobile cranes and boom truck cranes, wherein when such mobile and boom truck cranes include a swing-jib mounting system, the invention can be mounted to the standard crane tip swing-jib mounting plates already incorporated thereon, advantageously using the existing pinning holes and pins provided by the swing-jib boom system's manufacturer and without any added adaptation or modification to the crane. It is also contemplated for the present invention to be used with telescopic boom assemblies, and similarly where the telescopic boom assembly incorporates a swing-jib attachment system, the present invention becomes securely mounted to a boom assembly using only the previously mentioned swing-jib mounting plates and pins, and does not require any additional bolting, welding, or attachment of any other fixtures. Thus, the auto-powered leveling and rotation capability of the present invention, among its other features and advantages, can instantly transform any crane with a swing-jib attachment system into a modern day state-of-the-art aerial lift with an articulating boom section, which has not been done before. If desired, after its initial attachment to a mobile crane or boom truck crane, the present invention jib boom can remain permanently attached to the crane's main boom during road travel, which provides the important time-saving advantage of allowing an operator to instantly operate the jib boom after arrival at a new work location once the crane's outriggers are set. The present invention jib boom design also allows hydraulic rotation 360-degrees, which aligns it alongside its connected crane boom within the permitted envelope required for legal road travel. This continued connection of the present invention jib boom to a crane boom during road travel saves much labor, as current jib booms require many manual steps of attachment and detachment each time the connected crane is moved, as are identified below in this disclosure. Additional time saving is experienced when a work platform is attached to the distal end of the present invention jib boom, as personnel may enter the platform from the bed of the crane and instantaneously deploy the booms to position the platform in the desired elevated work area, and similar to the option of permanent attachment for the jib boom, a work platform connected to present invention jib boom may also have permanent attachment to it and does not have to be removed prior to road travel. Another advantage of the present invention jib boom is that its work range is not restricted to a linear line, as in the current state of art which only allows a jib boom to be attached to the crane so that the jib boom is in line with the crane boom. In contrast, the rotation feature of the present invention jib boom allows it to rotate in a horizontal plane regardless of the crane's boom angle, allowing the jib boom to wrap around objects in the work area, a distinct advantage over the prior art. The present invention jib boom also incorporates an articulating mechanism that enables it to articulate in the vertical plane regardless of the crane's boom angle. The rotation and articulating features together enable a crane with an attached present invention jib boom (with or without a platform) to be positioned and articulated in a manner that is not possible with the current state-of-art crane jib booms, providing a greatly increased work area envelope with more side reach and greater height. Since the present invention jib boom can hydraulically articulate, automatic leveling of it and an optionally attached work platform takes place as the crane boom is raised and lowered. In addition, the onboard powered-leveling systems of the present invention jib boom and work platform attachment maintain the jib boom and work platform in a level orientation as the attached crane boom is articulated up or down, regardless of the location of its load's center of gravity relative to the platform, including cantilevered and off-set loads. The present invention jib boom rotation mechanism also allows 360-degree platform rotation when fully-loaded, with the option of stable and balanced vertical articulation leveling and work platform rotation at the same time. Further advantages of the present invention include, but are not limited to, a redundant ground-operated radio remote control system having the same functions as the control box on the work platform, work platform positioning above the boom and boom tip that allows unrestricted work access above and around the crane boom tip, and legal road travel for the jib boom and work platform, as when the crane boom to which a present invention jib boom and work platform are attached is stowed over the chassis deck bed of a mobile crane or boom truck crane, the very compact and low profile design of the present invention jib boom and work platform allow it to fit within the permitted legal-road-travel envelope while it is secured to the boom tip swing-jib mounting plates (also referred to elsewhere herein as ‘swing-jib brackets’). In addition, since the present invention jib boom is a self-contained and fully functioning jib boom, it could also be attached to cranes and telescopic boom assemblies without a swing-jib attachment system, however, crane modification (bolting, welding, and/or other) is typically required to provide a secure jib boom attachment point.
2. Description of the Related Art
The mobile crane boom industry has advanced many new crane designs and other product technology over the last 15 years by adding new features and design improvements, such as stronger materials, onboard load-monitoring computers, optional radio remote controls that allow operation of all crane functions from the work platform, load-sensing computerized hydraulic systems, and much more. One area that has not advanced is swing jib booms, and those in use today are basically the same as 40 years ago. A description of what historically has been, and still is, standard for the crane industry regarding removable or pin-on jib booms follows below. Some disadvantages of this prior art are also mentioned below, along with information relating to dedicated work platforms having structure specific to a particular manufacturer or model.
The standard swing-jib boom currently used with boom truck cranes incorporates a four pin attachment system, which requires a lot of labor to attach and detach the jib boom. The procedural steps for prior art swing-jib boom attachment typically are: 1) Position the crane booms to one side of the truck chassis and deploy downward so that the crane tip sheave head is about 4-feet off ground, making the sheave head easily accessible for the operator to proceed with swing-jib boom attachment. 2) Retract the telescopic booms to allow holes on one side of two steel mounting plates located on the crane boom sheave head tip to line up with complementary holes on steel plates attached to the swing-jib boom while it remains supported by stowage brackets attached to the crane's main outer boom. 3) After aligning holes on the sheave head mounting plates with holes on the steel plates attached to the swing-jib boom, drive two tapered mounting pins through the aligned holes, which will act as a hinge point. 4) Tie a rope to the other (distal) end of the swing-jib boom. 5) Remove the restraints holding the swing-jib boom in place. 6) Raise the crane boom to a level position. 7) Using the rope manually pull the swing-jib boom 180-degrees about the hinge point. 8) Line up the unconnected holes in mounting plates on the crane boom sheave head tip with the remaining unconnected holes in the steel mounting plates attached to the swing-jib boom and drive the two remaining tapered mounting pins into the newly-aligned holes. 9) Remove the pull rope, and the swing-jib boom is now ready for use. In contrast, the present invention jib boom attachment has a hydraulically-powered rotation bearing drive assembly to mechanically rotate the jib boom to any position in a horizontally-extending plane. Thus, when the four tapered mounting pins are connected to the present invention jib boom assembly and the main crane boom sheave head tip, the present invention jib boom attachment can remain at least partially connected to the main crane boom while the hydraulically-powered rotation bearing drive assembly positions it anywhere in a 360-degree rotation range, including the preferred travel position alongside the crane's main boom within road legal width and height requirements.
The present invention jib boom attachment is also distinguishable from the manufacturer-dedicated jib booms currently in use with mobile crane booms. Mobile crane boom manufacturers do not currently offer, nor are mobile crane booms designed for, a factory-ready (or an after-market) self-contained jib boom that employs, adapts, and/or otherwise incorporates modern aerial lift features with powered rotation and jib boom self-leveling, and any attempt to do so by means other than the self-contained and self-powered jib boom attachment herein would require modification of the entire mobile crane boom assembly to supply the associated work platform with power (hydraulic or electric) for its needed jib boom leveling and rotational features, and would also require a new mechanically-designed platform mounting structure and assembly. Furthermore, for well over twenty years, many aerial lift boom trucks have had articulating booms with work platforms or baskets that allow them to function as aerial man lifts. While these articulating boom aerial lifts have many features and mechanisms that are similar to those of the instant invention, such as powered mechanical articulation and rotation, these aerial lifts are also designed and manufactured with many dedicated/integral components that work only with their own specifically designed product, and cannot be easily adapted for other use, such as being an after-market attachment to a mobile crane or boom truck crane. Furthermore, such aerial lift articulating booms are not self-contained, and power from the associated truck is needed for its work platform leveling and rotation functions. Thus, such prior art articulating booms are not designed to function as an after-market add-on jib boom and work platform attachment, as is the present invention, instead being an original and dedicated integral component of its associated aerial lift boom truck. In addition, these aerial lift boom trucks do not have a swing-jib or a boom tip designed sheave head configured for a swing-jib, and thus do not secure their booms or platforms in position using a standard swing-jib pinning system. Instead, they are all designed to be connected to attachment points specifically designed for support of their individual work platforms. Furthermore, in prior art and current aerial lift boom trucks, hydraulic or electrical power for work platform leveling and rotation is typically supplied from the ground by the supporting vehicle, an auxiliary engine, or a large battery-powered power unit, via hose/cable carriers or retractable reels attached to the boom assemblies, none of which are required during use of the self-contained self-powered present invention embodiments.
Thus, in contrast to the prior art, the present invention comprises the following features and advantages which make it structurally distinguishable. Leveling of the present invention jib boom with or without a work platform is accomplished by means of an onboard mechanically-powered automatic hydraulic/electronic leveling system that senses an out-of-level state in the jib boom or its attached work platform, and then operates a hydraulic leveling cylinder to articulate the jib boom with or without a work platform level while the crane boom is raised or lowered, regardless of the position of the work platform, onboard personnel, or its payload. When the crane boom is stopped, the jib boom's leveling cylinder employs several holding valves that lock the work platform into a level orientation. Thus, a loaded present invention jib boom can be safely rotated in the horizontal plane while it is in the locked position, and its load, including personnel, are also safe as a result of its powered-leveling while the boom is being raised or lowered. Also, in addition to powered-leveling, rotation will now be available on mobile cranes due to other integral design features of the present invention, including its strong rotational drive bearing assembly, a torsion-resistant tubular jib boom support structure, and a rigid and strong planar mounting bracket that anchors the present invention jib boom to the strong structural swing-jib sheave head while transferring all torsion and bending moments induced by off-set jib boom loads to the main crane boom's swing-jib sheave head.
In contrast to the current prior art mobile crane jib booms which lack any form of rotation, the present invention jib boom with or without an attached work platform advantageously incorporates a hydraulic-powered rotation bearing drive assembly that allows it to rotate in a 360-degree horizontal plane, with the present invention jib boom and an attached work platform being maintained automatically in a level state (or locked into a level orientation) during all of its 360-degree rotation range, and as the attached main crane boom is raised or lowered. Also, optionally, after the main crane boom stops vertical articulation, the level orientation of the present invention jib boom and an attached work platform can be locked during subsequent rotation with stops in its linear leveling actuator. Furthermore, the total power supply, mechanical actuation, and function controls in the self-contained most preferred embodiments of the present invention are all encompassed in a self-contained 12-volt battery-powered power pack integral with its jib boom assembly, thus eliminating the need for connecting hoses or power cables alongside the booms or an attached work platform, as well as eliminating the need for hose reels or cable carriers, unless applications dictate otherwise. In addition, a shear ball bearing and hydraulic gear drive mechanism in the present invention allows a dielectric-rated insulated jib boom and attached work platform to be used much like that of an aerial lift boom truck for working on live power lines. The universal-style mounting design of the present invention also allows it to be mounted to most commercial crane boom ends having a swing-jib mounting system, as the present invention is configured to use the swing-jib anchor points that most cranes now incorporate as a standard feature. As mentioned hereinabove, the prior art swing-jib mounting system allows for a simple four pin connection of the present invention jib boom and attached work platform to a main crane boom tip. In addition, the mechanically-powered leveling feature of the present invention jib boom allows for road-ready-stowed travel while at least partially attached to the main crane boom sheave head tip, enabling the attached jib boom to be rotated outboard into a substantially parallel position alongside a main crane boom within road-legal width and height requirements, while concurrently clearing the cab chassis roof and driver's vision, thus allowing the present invention jib boom with or without an attached work platform to remain connected to the main crane's boom tip during road travel to a next work site, saving significant set-up time at the next work location after the crane's outriggers are set.
The inventions thought to be most related in structure to the present invention, yet distinguishable, are those disclosed in U.S. Pat. No. 4,553,632 to Griffiths (1985), U.S. Pat. No. 7,926,670 to Schneider (2011), U.S. Pat. No. 4,537,281 to Endres et al. (1985), U.S. Pat. No. 4,653,654 to McDaniel, Jr. et al. (1987), U.S. Pat. No. 6,036,035 to Asano et al. (2000), U.S. Pat. No. 4,799,573 to Simnovec et al. (1989), and the three prior U.S. patents to the inventor herein for differing embodiments of a telescopic boom-mounted concrete pump apparatus having a pivotal jib boom member [U.S. Pat. No. 6,588,448 to Raymond (2003), U.S. Pat. No. 6,679,284 to Raymond (2004), and U.S. Pat. No. 6,823,888 to Raymond (2004)]. The Griffiths patent discloses an automatic leveling device for crane-boom-supported work baskets that senses and adjusts leveling via plumb sensors and potentiometers. The Griffiths invention also includes a battery that supplies power to an electronic leveling sensor, a servo valve, and an actuator for occasions when the basket needs to be electrically isolated from the ground. In 1983, when the Griffiths patent application was filed, others were making and using electronic leveling sensors on work baskets/platforms, such as those available from P-Q Controls in Bristol, Conn., but these baskets/platforms did not have onboard battery power. Also, after reading about the Griffiths invention, it is concluded that its basket is an integrally designed and incorporated part of its associated boom crane, as the Griffiths disclosure does not include any supportive layout instructions or design plans that would enable its basket to be an after-market work platform attachment. The Schneider invention discloses a gravity-leveling work platform that can be attached to the tip of a swing-jib crane boom and stowed for road-legal highway travel, however, the Schneider invention does not teach a work platform with the many features and advantages provided by the also stowable and road-legal present invention platform attachment. The Endres invention is a yoke-mounted platform having a gravity/pendulum leveling design and a brake that locks the leveled platform in-place when the boom is stopped, so that people can safely move around inside the platform without a risk of placing the platform in an out-of-level orientation. The Endres platform also incorporates a shock absorber that slows rotation of its arms 82 and 84 around pivot pins 94/96, which that could occur as a result of unbalancing movement by onboard personnel or payload before its lock/brake is released. After the 1985 Endres invention, newer art has similarly used a hydraulic cylinder with a fluid loop path from its extend side port to its retract side port (a plumbed-in line between the two ports being some sort of on/off hand-valve that stops fluid travel), which stops travel of the cylinder shaft and locks the work platform against further movement. Although the shock absorber of the Endres invention is important for those moving around inside its work platform (to prevent them from tipping out when any unbalanced movement occurs), a shock absorber feature is unnecessary in the present invention as a result of its onboard powered-leveling system. The McDaniels invention is a side-mounted gravity-leveled work platform that uses the swing-jib sheave head pinning point to attach itself to a crane boom. The side-mounted gravity-leveling system uses the same type of art employed in the Endres yoke-mounted platform system for leveling and locking its platform, which is distinguishable from the non-gravity-leveled present invention. The Simnovec invention is a self-leveling work platform with an overhead connection to a crane boom, and appears to be designed for a knuckle boom or an aerial lift boom. In contrast to the present invention, the Simnovec platform requires boom modification prior to its attachment. The McDaniels invention is a side-mounted gravity-leveled work platform that uses the swing-jib sheave head pinning point to attach itself to a crane boom. The side-mounted gravity-leveling system uses the same type of art employed in the Endres yoke-mounted platform system for leveling and locking its platform, which is distinguishable from the non-gravity-leveled present invention. The Simnovec invention is a self-leveling work platform with an overhead connection to a crane boom, and appears to be designed for a knuckle boom or an aerial lift boom. In contrast to the present invention, the Simnovec platform requires boom modification prior to its attachment. Also distinguishable from the present invention are the inventions disclosed in three prior U.S. patents to Raymond (now assigned to others) for a telescopic boom-mounted concrete pump apparatus, as its jib boom is designed for horizontal movement within a building to discharge concrete close to the location of the truck, with its pivoting capability used to maneuver it around columns, pillars, and other obstacles encountered within a building while attempting to reach the location requiring concrete. The three prior Raymond disclosures do not teach the self-contained and easily detachable present invention jib boom with its auto-powered leveling and rotation, and its attached work platform which instantly transforms any crane with a swing-jib attachment system into a modern day state-of-the-art aerial lift, with hydraulic articulation and automatic leveling of the present invention jib boom and an attached work platform able to occur as the crane boom is articulated up or down regardless of the location of its load's center of gravity relative to the work platform, including cantilevered and off-set loads, to provide a greatly increased work area envelope with more side reach and greater height. Also, with the work platform positioned above the boom and boom tip when its attached jib boom is articulated, unrestricted work access is possible above and around the crane's boom tip. The present invention jib boom rotation mechanism also allows 360-degree work platform rotation when fully-loaded, with the option of stable and balanced vertical articulation leveling and work platform rotation at the same time. Furthermore, the present invention jib boom articulating mechanism enables it to articulate in the vertical plane regardless of the crane's boom angle, while its rotation feature allows it to rotate 360-degrees in a horizontal plane regardless of the crane's boom angle, allowing the present invention jib boom to more easily wrap around objects in a work area. No other jib boom with optional work platform attachment for mobile and boom truck cranes is known to be self-contained and detachable, and also have the same structure or function, or to provide all of the features and advantages of the present invention.